Anything can be a roguelike if you stretch it far enough, even FTL and shit. It's even more abused than """"RPG""". At least Diablo was directly inspired by the original roguelikes. There's a design document out there. It says they literally just wanted to make a game like Angband/Moria with graphics, realtime, and eliminating some autistic shit like permadeath (at least by default) to sell more copies to normies.